Revuenon 135/2.8 -- Correct lens element arrangement?

[Class A]

Hi,

I got a Revuenon 135mm f/2.8 M42 lens. It looks like this one here, in the first image.

It is mostly made of plastic and had fungus but I thought before I throw it away, I'll have a go at repairing it.

The lens elements responded well to the removal of the fungus but I developed doubts as to whether the lens was put together correctly by the previous owner (who probably tinkered with it).

It has five elements, two at the rear group and three at the front. The way I found it was that the first element after the aperture is a convex lens with the bulbous part facing to the aperture. I've never seen anything like that in other telephoto 5-element lens diagrams. For instance, the Pentax 135/3.5 has this element facing to the other side, i.e., the bulbous part faces away from the aperture.

Having said that, given the parts -- three lenses (two convex, one concave and two spacers (one quite thick, one very thin), there doesn't seem to be another way of arranging the elements so that they do not touch each other. The thick spacer seems to be not quite thick enough to stop the convex element from touching the front element if I arrange them in a Sonnar arrangement. But perhaps it is supposed to touch it in the middle? Note that the concave element looks nothing like the one in the Sonnar design. Rather more like that of the Pentax 135/3.5 but one side seems to be flat.

The concave element fits within the thick spacer but has space around it so that it can move within it. That doesn't seem quite right either.

Does anyone have an idea regarding the correct way to put the lens together again?

If I knew what lens design that lens had, I could use a corresponding lens diagram for guidance.

I didn't take images with it when I got it because I wanted to remove the fungus first before I let it get into contact with my camera. Hence I don't know if the way it was assembled was correct. I could of course try all possible permutations that mechanically seem to make sense and see how the images turn out but that would take quite a while.

[Class A]

For some strange reason, the links I created in the above post all lead to "http://forum.mflenses.com/target=".

Here are the URLs as intended:

http://forum.mflenses.com/revuenon-135-f2-8-t15320.html

http://kmp.bdimitrov.de/lenses/primes/_optics/135f3.5-ii.gif

http://www.taunusreiter.de/Cameras/sonnar2.0.jpg

P.S.: As soon as I submit this post, the URLs in the first post work. When I deleted it, they went back to "http://forum.mflenses.com/target=". Is this some mechanisms to prevent first time posters from posting URLs?